There is known a disintegrator (USSR Inventor's Certificate No. 1,058,130) comprising a housing connected to a grinding chamber accommodating rotors with grinding wheels rotatable by electric motors. Provided between the rotor and housing is a separation zone wherethrough air is blown by means of pressure and suction blades. Connected to the housing is a pipe for evacuating finely ground material and air to a separator having the form of a cyclone with which a passage of return flow of air to the disintegrator communicates. The grinding chamber has an opening into the inlet pipe.
The material is charged through the inlet pipe to the grinding chamber, where it is comminuted by the rotors. Fine fraction of the material is blown off to be conveyed through the pipe for evacuating the fine fraction to the separator, whereas coarse fraction is conveyed through the opening in the grinding chamber to the inlet pipe for regrinding. From the separator air is conveyed along the air flow return passage to the disintegrator.
However, this prior art construction is bulky, and therefore takes much production space both horizontally and vertically. Another disadvantage is that much power is required for conveying material during operation of this disintegrator.
There is also known a disintegrator (U.S. Pat. No. 4,093,127) comprising a housing having inlet and outlet pipes and accommodating a rotor-separator fashioned as a drum with inclined separating plates spaced from one another about the circumference of the peripheral zone of the drum. A passage for discharging finely ground material and air is provided at the outside of the drum.
The material and air are conveyed from the inlet pipe to the rotor-separator. Rotation of the rotor causes the material to roll over, whereby lumps of the material are crushed and comminuted. Simultaneously, the rotor-separator is blown through by air. Particles having a size less than the clearance between the inclined separating plates are carried to the discharge passage and are evacuated through the outlet pipe. The material remains in the drum to complete comminution.
However, this disintegrator suffers from low efficiency of grinding; in addition, the entire unit including the rotor-separator and air feeding system is excessively bulky.
One more disintegrator is known (U.S. Pat. No. 2,656,988) comprising a housing with an inlet pipe accommodating a rotor with grinding blades and a rotor drive. The rotor is enclosed by a plurality of breaking and separating blades spaced from one another. The magnitude of clearance between the blades determines the boundary of material separation. The lower part of the housing accommodates collectors of coarse and finely ground materials with pipes for evacuating such materials, accordingly.
The material delivered for comminution falls onto the grinding blades of the rotor to be thrown to the plurality of the inclined breaking blades. Particles having a size smaller than the clearance between the breaking-separating blades pass therebetween to enter the collector of fine fraction material, whereas the other particles are conveyed to the collector of coarse material.
During operation the clearances between the blades tend to be clogged by the particles, whereby evacuation of the finely ground material becomes complicated. Also, because of only once-through comminution of the material the disintegrator is capable of producing relatively large-size particles as the end product. For reducing them further in size such large-size particles should be conveyed for repeated grinding to result in structural overcomplication of the disintegrator. The clearance between the blades needs also to be reduced thus again promoting clogging of the clearances and making the grinding process less efficient.
There is finally known a disintegrator (International Application PCT/SU No. 84/0060) comprising a housing, a grinding chamber having a cylindrical portion with a pipe for charging the initial material to the grinding chamber, and two side walls. The grinding chamber accommodates rotors made up of carrying disks with grinding wheels mounted on shafts of electric motors. Communicating with the grinding chamber is a passage for evacuating the material from the grinding chamber to the classifier which includes a plurality of inclined plates and is connected by a passage for discharging finely ground material with a cyclone-type separator. Connected to the separator is a passage of return flow of air to the disintegrator, whereas connected to the classifier is a passage for returning coarse fraction of the material to regrinding.
The material is carried with the air through the pipe to the grinding chamber where it is ground by the rotors and fed to the classifier in which the inclined plates act to separate fine fraction and convey it along the passage to the separator. Coarse fraction of the material flows from the classifier along the passage to the inlet pipe for regrinding.
This prior art disintegrator suffers from low efficiency, since after grinding the entire material is mixed and conveyed with air to the classifier for the coarse and fine fractions to be separated. A substantial amount of power is consumed for classification and transport of the fine fraction and air to the separator, and conveying air from the separator back to the disintegrator.